Apparatus for coating articles



y 1969 R. J. PERKEL 3,442,251

APPARATUS FOR COATING ARTICLES Filed Oct. 18, 1965 Sheet of 2 Ill/l71111/ [I [III I q AC R INVENTOR.

[Ill/l [I II I] I u ATTORNEYS May 6, 1969 Filed Oct. 18, 1965 R. J.PERKEL 3,442,251

APPARATUS FOR COATING ARTICLES Sheet of 2 m/vawroe ROBE/27 J. PER (ELBYGZLJMHOLL 75- United States Patent US. Cl. 118-9 2 Claims ABSTRACT OFTHE DISCLOSURE A metal coatingapparatus includes a container having arotary shaft supporting adjustable arm members forming a grid structurefor the work parts. At least two tanks which may contain a metalsolution and a reducing solution, respectively, are connected by pumpswith con duits extending through the container and having nozzles whichcan spray the solutions upon the work parts rotating along with thegrid. A centrifuge may be located below the container for removing metalresidue. The container may be provided with a motor operated cover. Themotors actuating the shaft, the pumps and the cover may be included in asingle circuit connected to a timing mechanism.

This invention relates to performing metallic depositions upon articlesto produce various effects such as mirror silvering and the like.

conventionally, metallic depositions have been placed upon articles byelectrical or electroless processes. For example, in mirror silveringthe process generally used is the application of a silver nitratesolution and a reducer solution to a surface which has been previouslycatalytically sensitized. The reducing solution, in the case ofelectroless deposition of silver, is composed of aldehydes, tartratesand other materials.

The apparatus of this invention set forth herein are particularlyconcerned with the electroless deposition of metallic films. Consideringmirror silvering for example, the conventional process of dipping themirror into the silvering solution is time consuming. Also, since only asmall percentage of the silvering solution is deposited on the work, theremaining silver is not utilized. Silver being a noble metal, somerecovery process mustbe utilized which is generally gravity filtrationand which still results in considerable loss of silver.

An object of the present invention is to avoid the disadvantages ofconventional processing and to produce deposition of metal rapidly andinexpensively.

Another object is to provide means for recovery of the unused noblemetal which are quick, rapid and inexpensive.

Other objects of the present invention will become apparent in thecourse of the following specification.

Optionally, the apparatus of the present invention may be utilized forthe deposition of both base metals and noble metals and will providemeans for recovery of the noble metal while permitting the base materialto leave the apparatus without application of recovery techniques andwithout interference with the recovery of the noble metal.

The invention will appear more clearly from the following detaileddescription when taken in connection with the accompanying drawingsshowing by way of example only, a preferred embodiment of the inventiveidea.

In the drawings:

FIGURE 1 is a front perspective view of one form of apparatus which maybe utilized to carry out the method of this invention. The cover of thedevice is shown in open position and the control board isdiagrammatically illus trated.

FIGURE 2 is a plan of the apparatus shown in FIG. 1 with the cover inopen position.

3,442,251 Patented May 6, 1969 FIGURE 3 is a front view of the apparatusshown in FIG. 2 with the cover in closed position but with portionsthereof broken away to show the internal structure.

FIGURE 4 is a right-side view of the apparatus shown in FIGS. 1 through3.

FIGURE 5 is a sectional view taken along line 5-5 of FIG. 3.

FIGURE 6 illustrates the centrifuge.

FIGURE 7 is a diagram showing the electrical connections.

As shown in the drawings, the apparatus of this invention comprises ahousing 11 which is supported upon a plurality of legs 12. Housing 11 isformed with a container portion 13 and a counterbalanced cover 14, whichmay be opened and closed by a small motor 4-0. Counterbalancing weights15 are connected to arms 16 which are connected to cover 14 on oppositesides thereof.

A work support 17 is disposed within portion 13 of housing 11. Worksupport 17 comprises a shaft 18 and a plurality of arm members 19secured thereto. Arm members 19 form a grid construction permittingsupport of the work to be operated on by the apparatus of thisinvention. Shaft 18 is connected to pulley 20, which in turn isconnected to pulley 21 by belt 22. Motor 23- bears shaft 24 which isconnected to pulley 21 so that work support 17 may be selectivelyrotated. Tanks 25 and 26 are adapted to contain solutions for metaldeposition and are terminated in conduits 27 and 28, respectively. Pumps29 and 30 intervene conduits 27 and 28 and conduits 31 and 32,respectively, so as to permit the application of pressure to thesolutions contained in tanks 25 and 26. Several conduits 31 ad 32terminate in spray nozzles 33 which are adapted to impinge upon the worksupport 17 between arm members 19 thereof.

Since the pumps may contain corrosive material, the machine and allexposed parts are preferably made of stainless steel.

Centrifuge 34 consists of rotor 35 and is disposed in operativerelationship with conduit 36 communicating with the bottom of container13. Rotor 35 of centrifuge 34 is electrically controlled by means of amotor 41. The centrifuge 34 is used to remove silver residue, so thatclear efiiuent can be removed through the pipe 42. The centrifuge can beemptied from time to time by removing the cover 43.

The machine is operated from the electrical console 44, the electricalconnections of which :are indicated only diagrammatically in FIG. 7since the timing mechanism is well known in the art and does notconstitute a part of the present invention.

With the foregoing specific description the operation of this inventionwill now be explained. In this explanation, by way of illustration, themethod used will be the method for electroless deposition of silver butit must be understood that other methods could also be em-' ployed.

A typical cycle begins when an operator depresses the master switch 15;then the cover 14 of housing 11 is opened by a small motor 40.Decorative glass parts indicated diagrammatically as 19a are supportedbetween arms 19 of work support 17. The parts have been presensitized bybeing immersed in a solution of stannous chloride. The arms 19 areadjustable so that they may support parts of different sizes. Tank 25 isfilled with ammoniacal silver nitrate and tank 26 with a reducingsolution which may contain formaldehyde and sugar. Cover 14- is nowclosed by reversing the rotation of motor 40 and pumps 27 and 28 areactuated for a preset period by the motor 23 energizing the solenoids 46and 47 of the pumps. Then a valve (not shown) is opened so that theexcess liquid flows through conduit 36. Centrifuge 34 is operated for apredetermined time period, causing the metal particles to adhere to thesolution. After completion of the centrifuging step, the eflluent ispermitted to drain through pipe 42.

It should be noted that the cam-operated timing mechanism electricallyconnected with the console 44 will automatically carry out all thesesteps after the master switch 45 is actuated and will automatically openthe switch when the operations are completed. The time for eachoperation is preset and can be varied by adjusting the timing mechanism.In the above example, for treating glass parts the spray and rotationcycles are adjusted for 15 seconds each while the centrifuge cyclecontinues for 30 seconds. Approximately the same time periods can beused for metallizing surfaces of parts molded of plastics, such asacrylonitrile butadiene styrene.

The method of this invention may also be carried out by two separatesteps, including a spraying of noble metal followed by a spraying ofbase metal. The noble metal step would be carried out as set forthabove. The base metal step would be similar except that the centrifuge34 would not be actuated since the recovery of the base metal is notimportant.

Also, in this invention, the metal and reducer solutions may be heatedby the inclusion of conventional heating devices in tanks 25 and 26,thermostats being used for proper temperature control.

While the machine is intended essentially for depositing metallic films,it can be also used for delivering a plurality of liquids simultaneouslyor sequentially to a racked part; obviously, it can be used toautomatically flow coat, wash or otherwise deposit a single liquid uponvarious parts.

The advantage of the machine of the present invention is that it willautomatically deposit metal and will automatically recover all metalwhich has not been deposited about three or four times faster than priorart methods. The number and size of pieces which can be metallizedsimultaneously is limited only by the size of the metallizing chamber.In the production of articles with reflective and decorative surfacesthe machine of the present invention involving a chemical reductionprocess, is at least as effective, and often more effective, than othermetallizing methods, such as vacuum metallizing. The machine can be alsoused effectively to render nonconductive surfaces of various articlesconductive since it will save considerable time and steps.

It is apparent that the example described above has been given solely byway of illustration and not by way of limitation and that it is subjectto many variations and modifications within the scope of the presentinvention. For example, when treating steel lamp bases a third tank andpump for a sensitizer are added to the apparatus. The sensitizer issprayed first and then the silver and reducer cycles are carried out inthe above described manner. Plastic parts may be coated with both silverand copper by using four tanks and pumps, one for silver, the second forits reducer, the third for copper and the fourth for its reducer. Inthat case consecutive cycles for silver and copper are used; thecentrifuge may be provided with a solenoid valve accepting the silverresidue and rejecting the copper residue. All such and other variationsand modifications are to be included within the scope of the presentinvention.

What is claimed is:

1. A metal coating apparatus, comprising a container, a swingable coverfor opening and closing said container, a rotary shaft mounted withinsaid container, a plurality of work-carrying arm members constituting agrid structure and adjustably mounted upon said shaft, at least twoseparate tanks for metal coating solution and reducing solutionrespectively, a separate pump connected with each tank, a separateconduit connected with each pump and extending into and within saidcontainer substantially parallel to said shaft, and spray nozzlescarried by each of said conduits and directed toward said gridstructure.

2. A metal coating apparatus in accordance with claim 1, comprising acentrifuge connected with an opening formed in the bottom of saidcontainer, said centrifuge having an outlet for the effluent, a motorfor swinging said cover, a motor for rotating said shaft, a motoractuating said centrifuge, and means electrically interconnecting saidmotors and said pumps to constitute a single timed electrical circuit.

References Cited UNITED STATES PATENTS 1,392,781 10/1921 Marsh et a1.134-109 X 2,785,999 3/1957 Ruthner 13410'9 X 2,889,837 6/1959 Braun etal 8326 X ROBERT W. MICHELL, Primary Examiner.

J. P. MCINTOSH, Assistant Examiner.

US. Cl. X.R.

